This section provides background information related to the present disclosure which is not necessarily prior art.
A projection device is a device which can project an image or a video and which can display a picture with a large size. The projection device is typically used in cooperation with a projection screen to improve the resolution of the displayed image and to enrich the colors of the displayed image for a better display effect. The projection device in real use needs to be adjusted so that the image projected by the projection device overlaps with a projection screen.
Earlier projection device were not difficult to adjust because the legacy projection devices required a large projection distance and were typically deployed at a meeting room or other similar places where the projection devices were frequently fixed on walls or other immobile positions. The projection devices were fixed in position so that it was convenient for human operators to adapt images projected by the projection device to projection screens.
In recent years, the technology of projection at an ultra-short focus has emerged along with the development of the projection technology so that the projection device can project a large image over a short projection distance. As a result, the projection device can be applied to entertainment at home. The projection device is typically moved very often in this application scenario, and the image may be deformed due to projection at the ultra-short focus, so the image projected by the projection device has to be debugged frequently. At present the projection device has to be debugged by a user adjusting manually the image projected by the projection device to overlap completely with the screen. It may take a long period of time to adjust manually the image, which may not be adjusted accurately.